A San Diego jury has found that Petco was not negligent when it sold a pet rat to a 10-year-old boy who later became sick and died after handling the animal.

Aidan Pankey died of an ailment known as rat bite fever, the result of a bacterial infection he contracted from a rat that was bred for sale as a pet.

A San Diego Superior Court jury deliberated about a day before reaching verdicts late Wednesday. The verdicts were read Thursday morning in Judge Eddie Sturgeon’s courtroom.

The panel found that Petco Animal Services Inc. knew or should have known that the pet rat was potentially dangerous when “used or misused” by a consumer in a reasonable manner. However, the jury said, Petco did not fail in its duty to adequately warn consumers of the potential danger and instruct them on how to handle rats safely.

They determined that neither Petco nor its supplier, Barney’s Pets, was negligent in this case.

Jury foreman James Wigdel of San Diego said the panel had “robust” discussions in the deliberation room. Ultimately, he said, the panel believed the defendants had taken significant steps to protect the community from disease by testing the animals and posting warnings for customers of the potential danger.

“They did what they could to prevent any kind of spread of disease,” Wigdel said.

The attorney who represented Petco at the trial did not speak to reporters after the verdicts were announced. The company released a statement on its website.

“We remain deeply saddened by the Pankey family’s tragic loss and are committed to continuing to provide the highest level of safety to our customers in the future,” the statement said. “The safety of people and pets is always Petco’s top priority.

“We agree with the jury’s ruling, which validates our position that proper care, protocols and guidelines were adhered to by Petco in this case.”

John Gomez, one of the lawyers representing the boy’s father, had asked the jury to award Andrew Pankey $20 million in damages for the loss of his son.

Outside the courtroom, Gomez said a major reason his client wanted the case to go to trial was to get the message out that many of Petco’s rats tested at random — about half, according to the plaintiff’s data — carried bacteria that could cause rat bite fever. He said the family plans to take the evidence they presented in court to lawmakers and public health agencies all over the country.

“I’m quite confident there’s going to be changes,” the attorney said, adding that he would file an appeal. “And then we’re going to come back and try this case again and we’re going to win it.”

Aidan’s grandmother, Sharon Pankey, said the lesson she hopes others take away from the case is “buyer beware.” She said customers should know they can ask Petco to test an individual rat for the presence of bacteria that could cause rat bite fever. And she warned other consumers that there’s a difference between a “healthy” rat and a “safe” rat.

“Don’t assume that something you buy from a big corporation is safe,” she said.

Aidan Pankey died in June 2013, about two weeks after he and his grandmother went to the pet supply store in Carmel Mountain Ranch and picked out a male rat he named Alex.

About two weeks later, Aidan became ill with flu-like symptoms and was taken to a doctor for treatment.

Thinking it was the flu, a pediatrician told him to rest, drink a lot of liquids and return for a follow-up visit a few days later if his health did not improve.

When Aidan’s symptoms worsened the next night, his family called paramedics. He was taken to the emergency room at Rady Children’s Hospital, where he died early the next morning.

Authorities determined he died of a result of streptobacillus moniliformis infection — rat bite fever.

There is no evidence that Aidan was actually bitten by Alex the rat, one of two rodents he kept as pets.

According to the Centers for Disease Control and Prevention, streptobacillus moniliformis is part of the normal respiratory flora of rodents. It can be transmitted from animals to humans through bites or scratches, or just by handling a rodent that carries it.

Rats that have this particular type of bacteria do not show any outward signs of disease or infection.

Andrew Pankey’s lawyers contended in trial that there had been at least 64 confirmed cases of rat bite fever contracted by customers since Petco began selling rats in 2001, but that the actual number, which would include Petco employees who became seriously ill, was 200 or higher.

Gomez, the father’s attorney, told the jury in his closing arguments that Petco should have stopped selling rats if the company was unable to provide animals that were free of this particular type of bacteria.

Petco’s lawyer argued that those numbers were inflated and that the father’s lawyers were ignoring the fact that the bacteria that causes rat bite fever cannot be bred out of the animals.

“It’s not illegal to sell rats,” said attorney Kimberly Oberrecht, adding that it’s “exceedingly” rare for humans to develop rat bite fever after coming in contact with the animals.

That’s especially true, she said, if people heed warnings to wash their hands after handling rats, and they remember not to share food, kiss or bathe with the animals.

Oberrecht said the company had sold around 5 million rats between 2001 and 2013, but she counted only 45 reported instances of rat bite fever.